1. Field of the Invention
The present invention relates to a vending machine for heating and dispensing food.
2. Prior Art
Vending machines for dispensing hot and cold drinks, candy, cookies, potato chips and other snack foods have enjoyed significant commercial success. However, vending machines for dispensing meals have been limited to dispensers of refrigerated foods such as sandwiches, salads and the like.
Devices heretofore devised for incorporating electronic ovens in food vending machines are disclosed in U.S. Pat. No. 3,333,666; U.S. Pat. No. 3,343,479; U.S. Pat. No. 3,386,550; U.S. Pat. No. 3,397,817; U.S. Pat. No. 3,534,676; U.S. Pat. No. 4,004,712; U.S. Pat. No. 4,398,651; U.S. Pat. No. 4,592,485; U.S. Pat. No. 4,762,250; U.S. Pat. No. 4,783,582 and U.S. Pat. No. 4,784,292.
Vending machines for hot meals generally include a refrigerated compartment for preserving food, a microwave oven compartment for fast cooking, and a conveyor for transferring food from the refrigerated compartment into the microwave oven. However, since vending machines for hot foods have enjoyed very limited commercial success, separate microwave ovens for heating food items removed from a refrigerator are commonly employed in convenience stores, airports, cafeterias and other food vending operations.
Microwave heating of certain foods, including pizza and sandwiches which contain dough and bakery products typically leaves the surface too moist and less palatable than similar food products cooked in other types of ovens.
Ovens of the type disclosed in U.S. Pat. No. 3,884,213; U.S. Pat. No. 4,154,861; U.S. Pat. No. 4,289,792; U.S. Pat. No. 4,409,453 and U.S. Pat. No. 4,835,351 employ air jets which impinge upon the surface of a food product to provide surface heating of the product in combination with microwave heating. Jet impingement ovens have enjoyed significant success in commercial food service and commercial food processing operations.
An important consideration in the dispensing of food products from vending machines is one of convenience. It is generally recognized that the desire to obtain food products from vending machines is heavily dependent upon considerations of time. In dispensing food products at room temperature, or at reduced temperatures, such considerations are not important since the desired food product can be vended directly from the storage compartment of the vending machine. However, in dispensing food products which need to be warmed, or even heated, considerations of time become significantly more important in that a certain amount of time is necessary to properly raise the temperature of the food product which is to be dispensed, prior to its delivery from the vending machine. Indeed, it is generally believed by those in the industry that time periods of even two or three minutes could represent a significant impediment to the interest on the part of the general public in obtaining heated food from a vending machine. Prevailing opinion is that consumer interest is generally limited to time periods on the order of one minute or less, representing a rather short period of time in which to completely heat and vend a given food product.
Yet another consideration is that of the food product which is to be dispensed from the vending machine. Certain types of foods are well suited to rapid heating techniques, using any of a variety of oven types (e.g., electric heating, infrared heating, convection heating, microwave heating, etc.). Examples of these are available with reference to the patents which are identified above. However, it has been found that some food products are not well suited to heating and dispensing from a vending machine. One example of this is the pizza, which the above-described devices are not well suited to handling.
A key reason for this is that despite the wide popularity of pizza, which is one of the most frequently consumed food types in the United States, food service companies have been unable to produce a frozen pizza which is suited to rapid heating and cooking techniques adaptable to a vending machine. Specifically, a pizza which is well suited to microwave cooking, one of the most rapid cooking techniques available, has not yet been developed. As a result of this, vending machines for handling pizza products have not been forthcoming.
The reasons for this are primarily two-fold. First, even the best so-called “microwavable” pizzas tend to be less than acceptable in consistency. Available pizza products exhibit drawbacks ranging from poor taste, to unacceptably doughy crusts, hard chewing crusts, uneven cooking, and at times, a cardboard-like consistency. Second, available “microwavable” pizzas could not, even under the best of circumstances, be cooked in less than approximately three minutes, significantly in excess of the period of time deemed advisable for maintaining consumer interest in obtaining a particular food product from a vending machine.
What is needed is an improved method and machine for cooking a pizza, so that the pizza crust is crisp and the cheese is melted and preferably browned.